BQ2012SN datasheet(11/20 Pages) TI

11 / 20 page

Command Register (CMDR)

The write-only CMDR register is accessed when eight

valid command bits have been received by the bq2012.

The CMDR register contains two fields:

W/R bit

Command address

The W/R bit of the command register is used to select

whether the received command is for a read or a write

function.

The W/R values are:

Where W/R is:

The bq2012 outputs the requested register

contents specified by the address portion of

CMDR.

The following eight bits should be written

to the register specified by the address por-

tion of CMDR.

The lower seven-bit field of CMDR contains the address

portion of the register to be accessed. Attempts to write

to invalid addresses are ignored.

Primary Status Flags Register (FLGS1)

The read-only FLGS1 register (address=01h) contains

the primary bq2012 flags.

The charge status flag (CHGS) is asserted when a

valid charge rate is detected.

Charge rate is deemed

valid when VSRO >VSRQ.A VSRO of less than VSRQ or

discharge activity clears CHGS.

The CHGS values are:

Where CHGS is:

Either discharge activity detected or VSRO <

VSRQ

1VSRO >VSRQ

The battery replaced flag (BRP) is asserted whenever

the potential on the SB pin (relative to VSS), VSB, falls

from above the maximum cell voltage, MCV (2.25V), or

rises above 0.1V.

The BRP flag is also set when the

bq2012 is reset (see the RST register description). BRP

is reset when either a valid charge action increments

NAC to be equal to LMD, or a valid charge action is de-

tected after the EDV1 flag is asserted. BRP = 1 signifies

that the device has been reset.

The BRP values are:

Where BRP is:

Battery is charged until NAC = LMD or dis-

charged until the EDV1 flag is asserted

1VSB dropping from above MCV, VSB rising

from below 0.1V, or a serial port initiated

reset has occurred

bq2012

FLGS1 Bits

CHGS

FLGS1 Bits

BRP

CMDR Bits

AD6 AD5

AD4

AD3

AD2

AD1

AD0

(LSB)

CMDR Bits

W/R

TD201201.eps

Break

0 0 0 0 0 0

1 0 1 0 0 1

Written by Host to bq2012

CMDR = 03h

Received by Host to bq2012

NAC = 65h

LSB

MSB

LSB

MSB

11 0

Figure 3. Typical Communication With the bq2012

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